Monday, February 24, 2014

Rosette stars - blue is hot

Not so long time ago Saint Valentine's Rosette appeared in my blog. A few days later I pictured a little bit of RGB light to this frame, so it is now more colorful. In the crop of the Rosette center you can see some star colors. The bright white-blue giants in the nebula center are the NGC2244 young open cluster stars. They are about 5200 light years away, and still seems to be as bright as the yellow star to the left and down of the center. But the yellow star is 12 Mon, and is only 560 light years away, so ten times closer. The yellow stars has surface temperature about 4000-5000K, oranges are in the range 2500-4000K, and there are also few pure red stars that are even colder. On the other side are blueish monsters with surface temperature 40000K and more. And this is only surface temperature - inside the stars there are termonuclear reactions running and there is a multimillion Kelvins hell.
So blue is hot :) 
And the full frame:

Clear skies!

Sunday, February 16, 2014

Saint Valentine's Rosette - update

NGC2244 is formal code of the star open cluster placed about 5000 light years away in the constellation Monoceros (Unicorn). The stars in this cluster are very young - the age is estimated to be less than 5 million years. They are hot and extremely luminous - brightest stars in this cluster are several hundreds thousands brighter than Sun! 
Open star cluster are usually not so exciting - just a bunch of stars placed close together. But in case of NGC2244 since they are so young there are still a lot of stuff the stars have been formed from. The star cluster is immersed in the large cloud of molecular hydrogen, and the stellar winds from the stars of the cluster are excerting pressure on interstellar clouds to cause compression followed by star formation that is still ongoing. This hydrogen cloud that surrounds NGC2244 star cluster is named Rosette Nebula.
X-ray observations of Rosette Nebula shows that its center emits copious amounts of X-rays due to the fact, that hot and young stars in the nebula center have heated surrounding gas to temperature 6 million kelvins. It seems to be quite intense place in the Universe.
The picture below has been taken on Valentine's day of year 2014 during the Full Moon, so the result is not quite excellent. 3 hours total exposure in hydrogen alpha emission line:
Only a center part of Rosette Nebula is shown - the nebula itself spans about two times wider.

Update - after making some required calibration flat files I processed the whole frame, so here it is:

Clear skies!

Monday, February 10, 2014

Retro Seven Sisters

The Pleiades or Seven Sisters is an open star cluster located in constellation Taurus. Contains middle aged (about 100 million years old), hot, blue and extremely luminous stars. The nebula surrounding stars is not formed by remnants left from the time the stars have been created, but unrelated dust cloud through which the stars are currently passing.
The Pleiades (M45) are prominous observing target in the winter sky (in northern hemisphere). Can be easily seen with naked eye - depending on the weather and sky conditions we can see up to seven brightest stars. It presents beautifully in binoculars, and in the larger telescopes we can see traces of the nebulosity surrounding cluster stars. Cluster is about 400 light years away, and its brightest stars are named for the seven sisters of Greek mythology: Sterope, Merope, Electra, Maia, Taygeta, Celaeno, and Alcyone.
'Retro' picture above has been exposed before Xmas 2013. Only luminance I was able to collect, but in fact the star and nebulosity color is blueish. I need to collect some more color and also luminocity exposures to make it look properly - so far so good :)
In this sky field of view there are also many faint galaxies, that can be noticed 'through' the star claster. In the enlarged picture above some of them have been marked with red lines. The apparent magnitude of these are about 17-19mag, and the distance is about million times larger (or more) than to the Pleiades itself.

Clear skies!

Sunday, February 9, 2014

Mirror figure tested by Perseus

At the end of last year I sent my telescope mirors to cover with fresh reflective layer of aluminium and also to improve its shape. So called 'mirror figuring' has been performed by experienced proffesional and the result is very good. The mirror shape differs from perfect paraboloid by less than 1/30 wavelength, that is less than 20 nanometers - that is less than 1/5000 of human hair diameter! The testing target has been famous Double Cluster in Perseus. 
The picture above is 150% enlarged fragment of the one of clusters center. Star shapes and resolution are remarkable, so the numbers don't lie :)
And below is the full double cluster frame. The clusters are about 7500 light years away from Earth. They are relatively young - about 12.8 million years. There are over 300 blueish  super giant stars in each of the cluster and both are approaching to us at speed 39km/s. 
Total exposure time for all color channels is mere 72 minutes, so no deep objects has been recorded - it was meant to be a test only, but since I have never pictures this clusters, I present it as well.

Clear skies!

Saturday, February 8, 2014

Elusive Orion

Winter is slowly fading away (hopefully) and during this time Orion has been shining at the sky with its gems. Among the bright Orion's stars there is also well known Orion Nebula. It is actually a part of the Orion Molecular Cloud Complex, so belongs to the same cloud of gas and dust as Horsehead Nebula. Orion Nebula (M42) is one of the brightest nebulaes - it is visible with naked eye under dark sky, and larger instruments (with aperture 10 inches or more) can show traces of colours there. It is definitely not elusive due to its low brightness - but because of my painful way of creating the pictures below. The nebula is placed about 1300 light years away and is the closest to the Earth star formation region
In the nebula center there is small and tight open star cluster called Trapezium. The five brightest stars of the Trapezium are on the order of 15-30 solar masses and are responsible for much of the illumination of the nebula.
On this particular picture I spent several nights of exposures (ten if I remember correctly). The nights were foggy and ruined by the Moon or incoming clouds, and the sky polution was every time different, so eventually during color processing I almost went crazy. Next winter I am going to get far away from city lights to catch this nebula.

Clear skies!